Message-ID: <A2D6CB88-8E63-43D0-B7CA-24FCFAFD46BC@u.washington.edu>
Date: 2013-11-01T18:20:58Z
From: Don McKenzie
Subject: extraction of roots in R
In-Reply-To: <CAEVDvzV88AK_NvvXatb4OWrCxPTfkYwF=AFCo+zR=A1-Wcad=w@mail.gmail.com>
If you just want the nth root of X, use X^(1/n)
> x <- 256
> x^(1/8)
[1] 2
> x <- -256
> x^(1/8)
[1] NaN
It appears that you get the positive real root.
Is this all you wanted?
On 1-Nov-13, at 11:11 AM, Gary Dong wrote:
> Dear R users,
>
> I wonder if R has a default function that I can use to do
> extraction of
> roots.
>
> Here is an example:
>
> X N
> 2.5 5
> 3.4 7
> 8.9 9
> 6.4 1
> 2.1 0
> 1.1 2
>
> I want to calculate Y = root(X)^N, where N represents the power.
> what is
> the easy way to do this?
>
> Thank you!
>
> Gary
>
> [[alternative HTML version deleted]]
>
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> and provide commented, minimal, self-contained, reproducible code.
Don McKenzie
Pacific Wildland Fire Sciences Lab
US Forest Service
Affiliate Professor
School of Environmental and Forest Sciences
University of Washington
dmck at uw.edu